This invention relates to the detection of ionizing radiation, particularly to a means for directing ionizations from natural and man-made sources, and more particularly to a detector of ionizing radiation which uses optical interferometry to detect density changes in a gas when charged particles pass through it.
Various types of detectors and detector systems have been developed for the detection of various levels of electromagnetic radiation and are utilized for various applications including surface contamination due to radiation, testing odd-shaped metal components used in processing radioactive materials, for sensing the position of neutral particles, measuring physical phenomena using optical interferometry, changes in the refractive index of a substance, optical fiber accelerometers, and for detecting chemical vapors in the air, to name as few applications. These prior known detectors and systems are exemplified by U.S. Pat. No. 5,004,914 issued Apr. 2, 1991 to V. Vali et al.; U.S. Pat. No. 4,950,074 issued Aug. 21, 1990 to N. Fabricius et al.; U.S. Pat. No. 4,829,821 issued May 16, 1989 to E. F. Carome; U.S. Pat. No. 4,733,967 issued Mar. 29, 1988 to G. E. Sommargron; and U.S. Pat. No. 4,522,495 issued Jun. 11, 1985 to P. Shajenko. In each of the above-referenced patents, a beam of electromagnetic radiation is first split, at least one arm of the beam is processed, and then the two beam arms are combined for determining the relation of characteristics of the arm of energy processed compared to the characteristics of the arm not processed.
while these prior detection devices and system are effective for certain applications, there is a need, particularly within the high energy physics community, to detect ionizing radiation, such as electrons, gamma rays, and muons, within extremely large sampling volumes of proposed detector systems to be built at the next generation of high energy particle accelerators. As an example, at the Superconducting Super Collider, two large detector systems are being proposed which will contain many different types of ionization counters to detect the by-products of high energy proton-proton collisions. These detector systems will use an extremely large number of separate detectors to reconstruct the many possible particle tracks, providing measurements of position, energy and momentum. This extremely large number of separate detectors makes it advantageous to consider replacing standard electronics with electro-optic components. Electro-optics allows for high density routing of fiber-optic cables, optical triggering, and immunity to stray radiation and electrical noise. Thus, with the proposed use of electro-optics, there is a need for an optical ionization detector for detecting charged particles.
The present invention fills this need by providing such an optical detector of ionizing radiation and which uses optical interferometry to detect density changes in a gas when charged particles pass through the gas.